This invention relates to a new and novel power drive mechanism for trailer landing gear and also pertains to a power drive mechanism arranged to convert a hand operated mechanism to a power mechanism.
Semi-trailers or similar vehicles are provided with front landing gear arranged to support the front of the trailer on the ground for loading or unloading the trailer while the tractor vehicle is detached. These landing gears have jack-type structures so that the front of the trailer can be raised or lowered for connecting the trailer to or disconnecting it from the tractor vehicle. Most landing gears of this type employ manual means for operating the jack structure. The jack structures have a cross driven shaft, a gear reduction assembly on the driven shaft, a drive shaft projecting from the gear reduction assembly, and a crank for manually operating the drive shaft. Such manually operated jack structures are difficult to operate and require considerable time in their operation. Powered lift mechanisms having heretofore been provided for various types of landing gear or dolley assemblies but such power mechanisms have the disadvantage that the power drive thereof requires special landing gear constructions which are complex in structure and expensive to manufacture. Thus, power drives of previous power driven mechanisms are not arranged for adaptation to existing landing gear assemblies. In addition, such mechanisms do not provide the option of allowing either powered or manual operation whereby the landing gears are inoperative in the event of a failure or absence of the source of power.